Photoelectric tube



May'5, 1942. E. H. B1KLEY PHOTO-ELECTRIC TUBE Filed July 6, 1959 mvmon Everewkle Patented May A, 1942 UNITED STATES PATENT OFFICE PHOTO-ELECTRIC TUBE Everett H. Bickley, BalaA Cynwyd, Pa. Application July 6; 1939, Serial No. 282,972

s claims." (ol.I 25o-165i The present invention relates to light sensitive apparatus and more particularly to photo'electric tubes of the electron emissive type.

Some of the objects of the present invention are to provide an improved photoelectric tube; to provide a photoelectric tube wherein a novel construction affords an extremely efficient electrical bond between the cathode conductor and the cathode lining of the tube at all times and one which does not deteriorate in use; to provide a simple and inexpensive tube construction whereby the tube and its associated internal parts can be easily and accurately assembled; to provide a contact spot of conducting material on the inner wall of a tube in position to be engaged by a cathode contactor acting under pressure; to provide a self-adjusting cathode contactor which, in assembly, requires only correct positioning for perfect contact operation; to provide means to uniformly deposit the cathode coating or lining on the inner Wall of a tube; to provide means for forming a contact between a cathode contacter and the cathode. coating of a photoelectric tube after the coating has been deposited on the tube; to provide a novel flag for so vaporizing and discharging electron emitting material that a more effective light sensitiveA lining is deposited on the inner wall of a tube; and to provide other improvements as will hereinafter appear. n

In the accompanying drawing Fig. l represents a side elevation, partly broken away, of a photoelectric tube embodying one form of the present invention; Fig. 2 represents a perspectivefof the tube and the assembly of electrodes as prepared for insertion in the tube for sealing therein; Fig. 3 represents a section on line 3 3 of Fig. 2; Fig. 4 represents a section on line 4 4 of Fig. 1; Fig. 5 represents a perspective of the `flag or electron active material receptacle as initially stamped for use; Fig. 6 represents a section of the complete flag as closed to retain the active material; Fig. `'I represents a fragmentary side elevation, partly broken away, of the tube of Fig. 1 showing a modified form of the invention with the cathode contactor as supported during the depositing of the cathode coating; Fig. 8. represents a section on line 8 8 of Fig. 7; and Fig. 9 represents a section on line 8--8 of Fig. 7 but showing-'the cathode conductor released to contact position. Figs. 3, 5 and 6 are on an enlarged scale for better illustration.

Referring to the drawing one form of the present invention comprises a glass body I0 of generally cylindrical shape which is open at one end in order to receive an electrode assembly II. This latter consists'of a glassclosure I 2 arranged to t within the open end .of the body I0 to seal the same and is preferably .formed with an annular flange I3 to contact with the circumferential marginal edge ofy the open end of the body I0. This closure is assembledwith anr anode rod I4 molded therein and welded to a' terminal wire I5 which projects from the flanged end for attachment to the proper prong I6 carried by the base I'I of the completed tube, Also. molded vtherein is a cathode conductor I8, one end of which is welded to a terminal wire 20 vleading through the flanged end for attachment to a second prong 2|. carried by the base .I1 and spaced from the prong I6.. The other end of the conductor I8 is welded or otherwise electrically bonded to two cathodel forming contactors 22 which are of a length to extend well into the body I0, when assembled, and each of which terminates inan L-shaped offset to provide an effective contact ,foot 23. These contactors 22 are of spring material and are so disposed that when inserted the body I0 each foot 213 will not only seat upon the inner'wall of theA body I0 but, dueto the angular disposition ofthe contactors 22; will place the spring material under such tension as will press the feet .23 constantly ragainst the aforesaid wall. The closure yI2'is also providedwith a glass exhaust pipe '24 extending axially exterior thereof between the terminals I5 and ZII-so that the assembled tube can be vevacuated and the pipe 24 sealed at the proper time by the application of a torch llame.

For the purpose of ensuring such an electrical bond between the feet 23 andthe lining 25 of metal deposited upon the inner wall of the body I0, a deposit 26 of a graphitic compound is attached to the said wallat a location to register with the position of the feet 23 when the contactors. 22 are located ingproperassembled position. While graphite preferablyforms the base of the aforesaid compound the invention is not so specifically limited because any other material may be used which does not vhave the characteristic of absorbing gases and then giving them off to the detriment of tube action.

In order to effect a uniform application of the metallic lining a novel ag has been devised compris'ing a metal stamping or otherwise 4formed rectangular piece 2'I provided' with two outwardly pressed pockets 28 each of which is formed with a through port 30. These pockets 28 are equally spaced from a transverse median line 3l about which the piece 21 is reversely bent in the direcand the other port 30 tion to bring the mouths of the pockets '28 into juxtaposition to thereby encase the electron emisl sive pellet 32. With freev ends of the piece 21 are overlapped and laterally bent to provide a tab 33 which is del signed to seat against the anode rod I4 and be welded thereto.

body or'tube I0 Iof the back to back construction one and by reason this operation completed the axially toward the opposite end. These dis'- charges have a wide angle of distribution' and lining.

result in -an extremely accurate uniform deposited As a means for preventing .stray current or i short circuiting between the anode I4 and ,the short sleeve 34 of glass or" lining 25, a relatively other non-conductor is s 'pped over the anode I4 ,to seat-'against the face of the closure. I2 and to which it becomes attached when'thef'closure is heated for sealing 'orother purpose.. This sleeve 34 has a bore ofsuflicientdiameterto provide a circumferential clearance about the anode I4 which serves effectively to interrupt any `current attempting to reach the lining 25. f s

In assembling the parts the body III with its deposit 26 properly attached to the inner wall is ready to receive the `electrode unit and this therefore is inserted through the open end of the body, care being Vtaken that the cathode spring wires are longitudinally alined with `the deposit 26. yWhen where the flange I3 abuts .the annular endv ofthe body I0, the feet of the cathode contactors rest upon the deposit 26 and firmly seat thereon by reasonV of the pressure of the deformed spring conductors. The flange I3 is now fused-,into sealing relation with the tube body I0 andthereafter thetube is evacuated by means ofthe exhaust': pipe 24. By now heatingltheinternal metal parts by electrical induction the active material is vaporized and discharges inV opposite f directions from the ag to meetk the cold inner wall ofthe body I 0 and condense thereon-in form of a relatively thin metallic liningVY of .substantially uniform thickness. .The exhaustpipe 24. can'now be sealed by atorch:flame properly directed.v Inthe. absence ofthe deposit :26`of conducting material the region adjacentlthefeet 23 would be bare of'lining deposit due .primarily to heatk dissipatedby the cathode wires under the bombarding ofthe flag. vantage is overcome because of the depositl26 which-even though sparsely k.coated still maintains :a perfect conducting relation between the .springs and the lining.- Following the formation Vofthe lining, 'a portion'of heatingflameat the. proper place to burn off sufficient of the llining to form a 'window 35 for the admission of the light rays Iby'which the tube action is controlled.. The ',amin'g may' be avoided yby using an anode of suitablefsize andaa deflection `of the vaporV will: beycaused 4during bombardment, thus preventing condensation. of

the vvapors on the glasswherethe .windovsl is.

desired.

In the form of 7, 8 and 9a high resistance -wire E.IIi,.lsuchn.as

the unit reaches the place I.

Any. such disadt,"

the tube is 'subjected to'. a f

the invention Y* shown. in Figs.

candescence as will result nickel of minute cross-section, is welded or otherwise made fast to the anode I4 and is formed with a laterally bent end 31 at such a distance from the anode I4 as will support the cathode contactors 22 out of contact with the wall of the tube III. Thus when these contactors 22 are held by the hook-like end 31 each will be bowed inwardly with increased spring area of the glass opposite the cathode feet will therefore be exposed to the bombardment and be coated the same .as the rest ofl the wall. n

vWhen the cathode coating is complete an electric current, either alternating or direct, is directed through the wire 36 to heat it to such inin thepressure of the spring contactors 22 bending the hook end 31 outwardly to a position where the contactors 22 are released and jump into contact pressing rela- A tion ywith the cathode coating.

In this way a perfect contact is obtained and maintained with the cathode. It will now beapparent that a photoelectric tube has been devised wherein provision is made for uniformly 'depositing .a cathode coating on the interior of the tube and with which a novel means of forming a cathode contact is employed to give highly satisfactory and eicient results.

Having thus described my invention, I claim: l. Aphotoelectric tube comprising an evacuated transparent body including a closure, a conductor passing through said yclosure and terminating'in an anode,y a second conductor passing through said closure andterminating in a spring contact tensioned in contactwith the inner wall of saidbody, a `cathode formed a by a metallic lining deposited on said-inner wall, and a spot of graphite Lcompound deposited. onsaid inner Wall to form an electrical bonding.. bridge between said .cathode and said .spring contact,

whereby electrical contactbetween'said spring contact and said `cathodeisindependentof physical contact between said .contact `conductorand said cathode. n l 2. A 'photoelectric tube comprising an evacuated glass body, a deposit of conducting material segregatedas a relatively small'spot on the inner wall of said '.body, a Ywindow formingfmetallic cathode deposited directly upon ,saidgla'ssibody as an "inner lining and overlapping said s'pot .deposit to form an electrical bond therewith,1a conductor leading axially from the exterior of saidV body tothe .interior thereof, saidconductor terminating in ya contactor spring pressed into 'electrical `contact with kvsaid deposit, 'an anode in said body, land aV conductor leading axially from said -anode to the exterior of said body.'

`3. vAphotoelectric tube comprisinglan evacuated glass body, a=deposit of'a -graphitic compound on theinner `wall of said' body,`said deposit being segregatedas a relatively small spot, a windowy forming .metallic cathode deposited A directly upon. said .glass body' as an inner lining and overlapping saidqspot deposit to -form .an electrical -bond"therewith, Ya `conductor leading axially from the exterior ofsaid body to the interior thereof, said conductor terminating'in a contactor spring pressed into electrical` contact with said deposit, an ar1ode'in1y said body;- and a conductor leading. axially fromsaid'y anode to the exterior of said body.

EVERTT: n. BrcxLYi tension and the 

